Reviewed on 6/23/2022

What Is Trichomoniasis?

Trichomoniasis Causes

Trichomoniasis is caused by Trichomonas vaginalis, a flagellated motile protozoan.

  • Approximately 174 million people worldwide are infected with this parasite each year, making it the most common curable sexually transmitted infection worldwide. In the U.S., it is estimated that about 3.7 million people have the infection. Only about 30% of these people will have any symptoms.
  • The average size of a trichomonad is 15 mm (they are not visible with the naked eye).
  • Reproduction of the parasites occurs every 8 to 12 hours.
  • Trichomonas vaginalis was isolated in 14% to 60% of male partners of infected women and in 67% to 100% of female partners of infected men. It is unclear why women are infected more often than men. One possibility is that prostatic fluid contains zinc and other substances that may be harmful to trichomonads.

Symptoms and Signs of Trichomoniasis

About 70% of people who are infected do not show any symptoms. When people do have symptoms, they can range in severity from mild to severe. Symptoms develop anywhere from 5 to 28 days after being infected, but some people can develop symptoms even later. The symptoms may improve or even go away and then return in some people. If untreated, the infection can persist for months to years. The following are the typical symptoms in those who do develop symptoms of trichomoniasis:

Trichomoniasis Symptoms in Women

  • Smelly, itchy, and typically frothy or foamy vaginal discharge
  • Vaginal itching
  • Yellow or gray-green discharge
  • Pain with urination possible

Trichomoniasis Symptoms in Men

  • Urethral discharge
  • Pain with urination
  • Pain and swelling in the scrotum (from epididymitis)

When to Seek Medical Care for Trichomoniasis

Vaginal or urethral itching and discharge or burning during urination should prompt a visit to the doctor.

Trichomoniasis can easily be diagnosed and treated by a doctor. If a doctor is unavailable or you do not have a doctor, seek treatment at an urgent care clinic, medical clinic, obstetric-gynecology clinic, or a hospital's emergency department.

Trichomoniasis Diagnosis

The diagnosis is made by directly observing the trichomonads on a sample of vaginal or urethral discharge through a microscope (they are too small to be seen by the naked eye).

  • Trichomonads are pear-shaped and have several flagella (whiplike tails) at one end.
  • This lab test is usually ordered only if the doctor suspects trichomoniasis as a possible diagnosis.
  • In some cases, the doctor may have to send the sample to the laboratory, and the result may not come back immediately.
  • The doctor will collect the specimen during a pelvic examination in women.
    • The doctor inserts a speculum into the vagina and then uses a cotton-tipped applicator to collect a sample.
    • The sample is then placed onto a microscope slide for observation.
    • Trichomonads are seen rarely during urine testing.
  • A diagnosis of trichomoniasis usually prompts a search for other sexually transmitted diseases, such as syphilis, HIV, gonorrhea, or Chlamydia.

Trichomoniasis Treatment

The treatment for trichomoniasis is antibiotics.

Trichomoniasis Home Remedies

The treatment of choice is antibiotics prescribed by the doctor. In addition to antibiotics, some alternative medicine therapies are available. These therapies have not been shown to be beneficial, and no rigorous scientific evidence supports their use. Home therapy should not be used instead of a doctor's visit and appropriate antibiotics, as this may allow the spread of the condition as well as other harmful sexually transmitted diseases, such as syphilis, HIV, gonorrhea, or chlamydia.

  • Some people feel that natural douches once a day while lying in a warm bath may help, but these are not substitutes for antibiotic treatment. To increase parasite-killing activity, you may add the juice of one lemon to either of the following douches:
    • Vinegar douche - 1 teaspoon vinegar to 1 quart warm water
    • Live-culture yogurt douche or a solution of Lactobacillus acidophilus - one-half teaspoon to one cup of water
  • Aromatherapy: Oil of bergamot (Citrus aurantium var bergamia) may help dry up irritating discharge. It can be used in douches or added to bath water.

Trichomoniasis Medical Treatment

The treatment of choice is metronidazole (Flagyl), except in the first trimester of pregnancy, when clotrimazole (Mycelex Troche)  is used topically. It is important not to drink alcohol while taking this drug (the combination can lead to abdominal pain and vomiting).

Metronidazole (Flagyl)

  • A large single dose is as effective as longer term treatment, but increases the risk of side effects such as nausea and vomiting.
  • Pills taken twice a day for 7 days is an alternative.

Clotrimazole (Gyne-Lotrimin, Mycelex-7) if pregnant and having symptoms

  • Medicine is inserted into the vagina at night for 14 days.
  • This will decrease symptoms, but the cure rate is only 20%.


  • Because infected male partners often do not have any symptoms, they do not seek medical care. It is important, however, that all sexual partners are evaluated and treated. Otherwise the person may become reinfected.
  • Male partners are treated with one large dose of metronidazole or may be treated for 7 days.
  • The doctor may not routinely write an additional prescription for the infected individual's partner without evaluating him or her first.

Trichomoniasis Prevention

Because trichomoniasis is a sexually transmitted disease, abstinence is the only method to absolutely avoid the contraction of this disease. Safe sex and hygiene practices may also help prevent Trichomonas infection.

  • Wear condoms (this reduces but does not completely eliminate the possibility of contracting Trichomonas infection.
  • Wash before and after intercourse.
  • Don't share swimsuits or towels. (Trichomonads survive for up to 45 minutes outside the body.)
  • Shower immediately after swimming in a public pool.

Trichomoniasis Prognosis

Trichomoniasis is not very serious, but it is contagious. If untreated, it may infect tissues throughout the urinary tract and reproductive system. Trichomoniasis may lead to preterm labor if left untreated during pregnancy. Trichomonas infection may also cause inflammation and irritation of the genital areas that makes it easier to transmit and acquire HIV infection. About 20% of people who are treated develop a recurrent infection.

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Vaginal Infection Symptoms

Trichomoniasis Causes

Trichomoniasis causes a frothy vaginal discharge that may be yellow-green or gray, itching and irritation of the genitals, burning with urination (sometimes confused with a urinary tract infection), discomfort during intercourse, and a foul smell. Because trichomoniasis is a sexually-transmitted disease, symptoms may appear within 4-20 days after exposure. Men rarely have symptoms, but if they do, they may have a thin, whitish discharge from the penis and painful or difficult urination.

Reviewed on 6/23/2022
Medically reviewed by Wayne Blocker, MD; Board Certified Obstetrics and Gynecology


United States. "Trichomoniasis."